1. Field of the Invention
The present invention relates to a magneto generator which generates electricity under the electromagnetic induction action of permanent magnets and magneto coils in accordance with the rotation of a flywheel.
2. Description of the Related Art
In the past, there has been known a magneto generator in which a plurality of permanent magnets are arranged in a circumferential direction on an inner peripheral wall surface of a bowl-shaped flywheel while being positioned by a plurality of concave and convex portions formed on a cylindrical portion of the flywheel at equal intervals (see, for instance, a first patent document: Japanese patent publication No. H6-81437).
In order to raise the power generation efficiency of the magneto generator, it is necessary to reduce a gap (air gap) between the flywheel and a stator arranged at an inner side of the flywheel as much as possible, and to that end, the flywheel is required to have high roundness or circularity.
In the magneto generator as constructed above, however, the above-mentioned concave and convex portions are formed, for example, by driving a punch to an intermediate portion of the cylindrical portion of the flywheel at four locations spaced apart at equal intervals, and in this case, there arises a problem that the roundness or circularity of the flywheel might be reduced during the punching operation, thus resulting in difficulty in obtaining the flywheel with a high degree of circularity.
In particular, there is a problem that in case where the cylindrical portion of the flywheel, the thickness of which is decreased for reduction in size and weight thereof, is embossed or punched out from outside, it is difficult to provide the flywheel with a predetermined roundness or circularity.